diff options
Diffstat (limited to 'gr-atsc/lib/qa_atsci_fake_single_viterbi.cc')
| -rw-r--r-- | gr-atsc/lib/qa_atsci_fake_single_viterbi.cc | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/gr-atsc/lib/qa_atsci_fake_single_viterbi.cc b/gr-atsc/lib/qa_atsci_fake_single_viterbi.cc new file mode 100644 index 0000000000..88e2fdb929 --- /dev/null +++ b/gr-atsc/lib/qa_atsci_fake_single_viterbi.cc @@ -0,0 +1,144 @@ +/* -*- c++ -*- */ +/* + * Copyright 2002 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3, or (at your option) + * any later version. + * + * GNU Radio is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, + * Boston, MA 02110-1301, USA. + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <cppunit/TestAssert.h> +#include <stdio.h> +#include <atsc/fake_single_viterbi_impl.h> +#include "qa_atsci_fake_single_viterbi.h" +#include <random.h> +#include <string.h> + + +static const int NTRIALS = 50; +static const int MAXERRORS = 10; +static const int NN = 200; + +static const int MAXDIBIT = 3; + +void +qa_atsci_fake_single_viterbi::encode_block (unsigned char *out, unsigned char *in, + unsigned int n) +{ + for (unsigned int i = 0; i < n; i++) { + out[i] = encoder.encode(in[i]); + } +} + + +void +qa_atsci_fake_single_viterbi::decode_block (unsigned char *out, unsigned char *in, + unsigned int n) +{ + for (unsigned int i = 0; i < n; i++) { + out[i] = decoder.decode ((2*in[i]-7) + noise ()); + } +} + +float +qa_atsci_fake_single_viterbi::noise () +{ +#if 1 + return 2.0 * ((float) random () / RANDOM_MAX - 0.5);; +#else + return 0; +#endif +} + +void +qa_atsci_fake_single_viterbi::t0 () +{ + static const int blocklen = NN; + unsigned char in[blocklen]; + unsigned char enc[blocklen]; + unsigned char out[blocklen]; + int decoder_errors = 0; + int delay = decoder.delay (); + int i; + + // printf (" Delay is %d.\n", delay); + + srandom (27); // reproducable sequence of "random" values + + for (int nt = 0; nt < NTRIALS; nt++){ + + // load block with random data and encode + + for (i = 0; i < (blocklen-delay); i++) + in[i] = random () & MAXDIBIT; + for ( ; i < blocklen; i++) + in[i] = 0; /* To empty the delay buffers */ + + encoder.reset (); + encode_block (enc, in, blocklen); + + decoder.reset (); + + // decode the block + decode_block (out, enc, blocklen); + + // int offset = delay/4; + int offset = 2; + bool differs = (memcmp (in+offset, + out+delay+offset, blocklen-(delay+offset))); + + // initial values after reset are 0 + for (i = 0; i < delay; i++){ + if (out[i] != 0) + printf (" initial output at %i is %X, not 0\n", + i, out[i]); + } + + if (differs){ + printf (" incorrect data, trial #%d\n", nt); + + printf ("\n Erroneous result dibits:"); + for (int erri = 0; erri < (NN-delay); erri++) { + if (in[erri] != out[erri+delay]) + printf (" %d", erri); + } + printf ("\n In: "); + for (int erri = 0; erri < (NN-delay); erri++) { + printf (" %d", in[erri]); + } + printf ("\n Out: "); + for (int erri = 0; erri < (NN-delay); erri++) { + printf (" %d", out[erri+delay]); + } + printf ("\n Errs:"); + for (int erri = 0; erri < (NN-delay); erri++) { + printf (" %c", (in[erri] != out[erri+delay])? '*': ' '); + } + printf ("\n THIS IS A REAL PROBLEM.\n"); + decoder_errors++; + } + } + + printf (" Summary: %d decoder errors out of %d trials.\n", + decoder_errors, NTRIALS); + + CPPUNIT_ASSERT (decoder_errors == 0); +} + |